This invention relates to a scroll compressor with a lubrication system for indirectly conveying lubricant to the back pressure chamber seals.
Scroll compressors are becoming widely utilized in refrigerant compression applications. Essentially, a scroll compressor consists of two scroll members with one orbiting relative to the other. Each scroll members includes a spiral wrap extending from a base. The spiral wraps interfit to define compression pockets. As the orbiting scroll moves relative to the non-orbiting scroll, the size of compression pockets becomes smaller and fluid trapped inside the pockets becomes compressed. There is a separating force generated from the compressed fluid tending to bias the two scroll members away from each other.
To counteract the separating force, it is known to tap a pressurized fluid to a chamber behind the base of one of the scroll wraps. Two seals typically define the boundaries of the chamber. Pressure in the back chamber acting over the scroll base creates a force tending to bias the scroll members back together, and acts in a direction opposite to the separating force discussed above.
The back pressure chamber seals are subject to many challenges and, in known compressors, often fail. One cause of seal failure is the lack of oil to lubricate seals.
It has been proposed in the past to deliver lubricant directly to the back chamber seals. In such proposals the oil needs to be additionally pressurized, thus creating complications. First, the compressor needs means for pressurizing the oil. Also, the seals may be damaged due to overcompression of the oil in the supply line. Also, the slight axial movement of the orbiting scroll can overcompress oil in the back chamber, creating another cause of seal damage.